1. Field of the Invention
The present invention relates to fixing apparatuses for heat sinks, and particularly to a fixing apparatus which provides uniform pressure distribution.
2. Related Art
With the rapid development of computers, the processing speeds of the processing units of computers have become faster and faster. As a result, a modern processing unit consumes considerable electronic energy and generates much heat. To prevent a processing unit from overheating, it is conventional to install a heat sink pressing against the processing unit. Typically, a fixing apparatus is needed to firmly press the heat sink against the processing unit.
A conventional fixing apparatus as disclosed in U.S. Pat. No. 5,671,118 is used to press a heat sink against a processing unit. Referring to FIG. 3, a channel 12 is defined in a central portion of the heat sink 10. The fixing apparatus 14 is received in the channel 12. Two engaging portions 24 are provided on opposite ends of a socket 22. The fixing apparatus 14 can engage with the engaging portions 24, and thereby firmly press the heat sink 10 against the processing unit 20.
However, the fixing apparatus 14 only presses on a middle portion of the heat sink 10. As a result, the pressure distribution is not uniform, and the heat dissipating efficiency of the heat sink 10 is diminished. This is particularly in the case when the heat sink 10 is large. In addition, a fan can not be attached onto the fixing apparatus 14 to provide forced ventilation for the heat sink 10.